Hi guys,

What can you say about the relationships of my database model,

Please disregard the datatypes, I'm only interested to hear from you guys regarding the relationships of the tables.
For example on 'Classes' table It is a FK on 'Parts' and 'Media' tables is this fine?
One parent table two children tables is this okay.

Also any improvements you can suggest like the look-up table or junction table.
Or flaws that you will notice?

Thanks in advance.